Most athletic shoes used for field sports, such as football, baseball, softball, soccer, rugby and lacrosse, have a number of projections or cleats for the purpose of increasing traction. (The terms "cleats" and "projections" will be used interchangeably herein.) Cleats penetrate the turf to prevent slipping during starting, stopping, and cutting maneuvers.
Such projections, however, in addition to providing desirable traction for starting, stopping and cutting, typically provide very undesirable resistance to pivoting. This can be a disadvantage in two ways.
When pivoting is inhibited, the maneuverability of an athlete is limited. His performance is less than it could be. Enhancing the ability of a player to pivot can greatly increase his effectiveness on the field.
In addition to inhibiting certain athletic pivoting actions, projections or cleats of the prior art tend to resist tension-relieving pivoting when unwanted torque or force is applied to the athlete, particularly to a leg. If a leg is forcibly twisted when the cleats have penetrated into the turf, and the foot is held firmly on the turf, the projections or cleats can prevent pivoting and thereby lead to injuries, particularly common knee injuries.
While athletic shoes for use on artificial turf typically have cleats or projections of shorter length than shoes for natural grass, the same problems are experienced. Athletic shoes for artificial turf playing surfaces typically compensate for the reduced length of their cleats or projections by increasing the number of projections. The problems mentioned above are present in varying degrees in shoes designed for use on artificial turf, and improved pivot cleating is needed for such shoes. Indeed, even with flat-soled artificial turf shoes, pivoting is often strongly resisted; this may be because of surface adhesion, rather than penetration.
A wide variety of attempts have been made in the past to make an athletic shoe which would improve pivoting. Among these are shoes with separate spikes or widely spaced arced edges and shoes with fixed annular cleats. Those with separate spikes or widely spaced arced edges tend to resist pivoting. This invention relates generally to constructions having fixed annular cleats.
Prior art shoes of the latter type, having continuous annular cleats, have failed to provide adequate gripping action and/or have failed to provide adequate pivoting action for several specific reasons. Such shoes have not been accepted by athletes and have not been widely in use.
The deficiencies of such prior art shoes and the unique characteristics and advantages of this invention can most easily be described with reference to the foot of the athlete. The sole of the foot includes four basic portions. They are, in order back to front: the heel portion; the arch portion; the ball-of-the-foot portion; and the toe portion. The heel portion and the ball-of-the-foot portion are those portions which share most if not all of the player's weight when the player is in a normal standing position with his feet generally flat on the ground. In such position, the arch portion of the sole bears little if any weight, and the toe portion bears little if any weight.
When a player is "on his toes" in a "ready" position, virtually all of the player's weight is normally shared by the toe and ball-of-the-foot portions. The same is usually true when a player is "digging" in a running action. Indeed, when a player is in the ready position, the juncture of the phalanges (toe bones) and the metatarsles is the center of weight bearing. In other words, the center of weight bearing in the forward portions of the foot actually moves forward when a player shifts to the ready position.
The sole of an athletic shoe has portions immediately below such four foot portions which may be designated, and herein are designated, by the same terms.
Prior art shoes having annular cleating fail to function properly at least in part because of grossly improper placement of an annular cleat--much too far back from the juncture of the toe and ball-of-the-foot portions where weight is centered in the ready position. Indeed, in the ready position, normally the only position in which pivoting is important, such prior shoes would pivot little better than shoes with the standard blade-like or tapered cleats.
Further affecting the performance of some of the prior art shoes with fixed annular cleats is the fact that a portion of the sole enclosed by the annular cleat is raised above the main sole surface, thus preventing complete penetration of the cleats into the turf and limiting the available traction. Another drawback is the small diameter of some annular cleats. Such cleats do not provide a wide-based bearing on the ground, causing instability and insufficient pivoting and traction.
Without further elaboration on the shortcomings of prior athletic shoes, it can be said that prior shoes have failed to provide a combination of good traction and good pivotability. There has been a strong, unsatisfied need for an improved athletic shoe for field sports, including a need for shoes providing improved pivotability with good stability and traction on artificial turf playing surfaces.